1 | #include "../shaderenv.h"
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2 |
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3 |
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4 | ////////////////////
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5 | // Screen Spaced Ambient Occlusion shader
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6 | // based on shader of Alexander Kusternig
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7 |
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8 |
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9 | #define USE_EYESPACE_DEPTH 1
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10 |
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11 |
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12 | struct fragment
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13 | {
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14 | float2 texCoord: TEXCOORD0;
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15 | float3 view: TEXCOORD1;
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16 | };
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17 |
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18 |
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19 | struct pixel
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20 | {
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21 | float4 illum_col: COLOR0;
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22 | };
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23 |
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24 |
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25 | inline float occlusionPower(float radius, float dist)
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26 | {
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27 | return 6.283185307179586476925286766559f * (1.0f - cos(asin(radius / dist)));
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28 | }
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29 |
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30 |
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31 | inline float SqrLen(float3 v)
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32 | {
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33 | return v.x * v.x + v.y * v.y + v.z * v.z;
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34 | }
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35 |
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36 |
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37 | inline float2 myreflect(float2 pt, float2 n)
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38 | {
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39 | // distance to plane
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40 | float d = dot(n, pt);
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41 | // reflect around plane
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42 | float2 rpt = pt - d * 2.0f * n;
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43 |
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44 | return rpt;
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45 | }
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46 |
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47 |
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48 | inline float3 Interpol(float2 w, float3 bl, float3 br, float3 tl, float3 tr)
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49 | {
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50 | float3 x1 = lerp(bl, tl, w.y);
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51 | float3 x2 = lerp(br, tr, w.y);
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52 | float3 v = lerp(x1, x2, w.x);
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53 |
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54 | return v;
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55 | }
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56 |
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57 |
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58 | // reconstruct world space position
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59 | inline float3 ReconstructSamplePos(float eyeSpaceDepth,
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60 | float2 texcoord,
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61 | float3 bl, float3 br, float3 tl, float3 tr)
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62 | {
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63 | float3 viewVec = Interpol(texcoord, bl, br, tl, tr);
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64 | float3 samplePos = -viewVec * eyeSpaceDepth;
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65 |
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66 | return samplePos;
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67 | }
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68 |
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69 |
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70 |
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71 | /** This shader computes the reprojection and stores
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72 | the ssao value of the old pixel as well as the
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73 | weight of the pixel in the new frame.
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74 | */
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75 | inline float2 temporalSmoothing(float4 worldPos,
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76 | float eyeSpaceDepth,
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77 | float2 texcoord0,
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78 | float3 oldEyePos,
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79 | sampler2D oldTex,
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80 | float4x4 oldModelViewProj,
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81 | sampler2D colors,
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82 | float3 projPos,
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83 | float invW,
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84 | float3 oldbl,
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85 | float3 oldbr,
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86 | float3 oldtl,
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87 | float3 oldtr,
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88 | float3 diffVec
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89 | )
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90 | {
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91 | // compute position from old frame for dynamic objects + translational portion
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92 | const float3 translatedPos = diffVec - oldEyePos + worldPos.xyz;
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93 |
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94 |
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95 | /////////////////
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96 | //-- reproject into old frame and calculate texture position of sample in old frame
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97 |
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98 | // note: the old model view matrix only holds the view orientation part
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99 | float4 backProjPos = mul(oldModelViewProj, float4(translatedPos, 1.0f));
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100 | backProjPos /= backProjPos.w;
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101 |
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102 | // fit from unit cube into 0 .. 1
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103 | const float2 oldTexCoords = backProjPos.xy * 0.5f + 0.5f;
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104 | // retrieve the sample from the last frame
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105 | const float4 oldPixel = tex2Dlod(oldTex, float4(oldTexCoords, .0f, .0f));
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106 |
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107 | #if USE_EYESPACE_DEPTH
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108 |
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109 | // calculate eye space position of sample in old frame
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110 | const float oldEyeSpaceDepth = oldPixel.w;
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111 |
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112 | // vector from eye pos to old sample
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113 | const float3 viewVec = Interpol(oldTexCoords, oldbl, oldbr, oldtl, oldtr);
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114 | const float invLen = 1.0f / length(viewVec);
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115 | const float projectedEyeSpaceDepth = invLen * length(translatedPos);
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116 | //const float projectedEyeSpaceDepth = length(translatedPos);
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117 |
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118 | const float depthDif = abs(1.0f - oldEyeSpaceDepth / projectedEyeSpaceDepth);
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119 |
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120 | #else
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121 |
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122 | // calculate eye space position of sample in old frame
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123 | const float oldDepth = oldPixel.w;
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124 | // the depth projected into the old frame
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125 | const float projectedDepth = projPos.z;
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126 | // calculate depth difference
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127 | const float depthDif = abs(projectedDepth - oldDepth);
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128 |
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129 | #endif
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130 |
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131 | float newWeight;
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132 |
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133 | if (1
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134 | && (oldTexCoords.x >= 0.0f) && (oldTexCoords.x < 1.0f)
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135 | && (oldTexCoords.y >= 0.0f) && (oldTexCoords.y < 1.0f)
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136 | && (depthDif <= MIN_DEPTH_DIFF)
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137 | )
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138 | {
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139 | // increase the weight for convergence
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140 | newWeight = oldPixel.y;
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141 | }
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142 | else
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143 | {
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144 | newWeight = 0.0f;
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145 | }
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146 |
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147 | return float2(oldPixel.x, newWeight);
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148 | }
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149 |
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150 |
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151 | /** The ssao shader returning the an intensity value between 0 and 1
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152 | This version of the ssao shader uses the dotproduct between pixel and
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153 | sample normal as weight.
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154 | */
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155 | float3 ssao2(fragment IN,
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156 | sampler2D colors,
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157 | sampler2D noiseTex,
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158 | float2 samples[NUM_SAMPLES],
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159 | float3 normal,
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160 | float3 centerPosition,
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161 | float scaleFactor,
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162 | float3 bl,
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163 | float3 br,
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164 | float3 tl,
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165 | float3 tr,
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166 | float3 viewDir,
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167 | sampler2D normalTex
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168 | )
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169 | {
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170 | // Check in a circular area around the current position.
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171 | // Shoot vectors to the positions there, and check the angle to these positions.
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172 | // Summing up these angles gives an estimation of the occlusion at the current position.
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173 |
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174 | float total_ao = .0f;
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175 | float numSamples = .0f;
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176 | float validSamples = .0f;
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177 |
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178 | for (int i = 0; i < NUM_SAMPLES; ++ i)
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179 | {
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180 | const float2 offset = samples[i];
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181 |
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182 | #if 1
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183 | ////////////////////
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184 | //-- add random noise: reflect around random normal vector (rather slow!)
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185 |
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186 | const float2 mynoise = tex2Dlod(noiseTex, float4(IN.texCoord * 4.0f, 0, 0)).xy;
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187 | const float2 offsetTransformed = myreflect(offset, mynoise);
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188 | #else
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189 | const float2 offsetTransformed = offset;
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190 | #endif
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191 | // weight with projected coordinate to reach similar kernel size for near and far
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192 | //const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor + jitter;
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193 | const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor;
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194 |
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195 | //if ((texcoord.x <= 1.0f) && (texcoord.x >= 0.0f) && (texcoord.y <= 1.0f) && (texcoord.y >= 0.0f)) ++ numSamples;
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196 | float4 sampleColor = tex2Dlod(colors, float4(texcoord, 0, 0));
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197 |
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198 | const float3 samplePos = ReconstructSamplePos(sampleColor.w, texcoord, bl, br, tl, tr);
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199 | // the normal of the current sample
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200 | //const float3 sampleNormal = normalize(tex2Dlod(normalTex, float4(texcoord, 0, 0)).xyz);
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201 | const float3 sampleNormal = tex2Dlod(normalTex, float4(texcoord, 0, 0)).xyz;
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202 |
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203 |
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204 | ////////////////
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205 | //-- compute contribution of sample using the direction and angle
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206 |
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207 | float3 dirSample = samplePos - centerPosition;
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208 |
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209 | const float sqrLen = max(SqrLen(dirSample), 1e-2f);
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210 | const float lengthToSample = sqrt(sqrLen);
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211 | //const float lengthToSample = max(length(dirSample), 1e-6f);
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212 |
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213 | dirSample /= lengthToSample; // normalize
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214 |
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215 | // angle between current normal and direction to sample controls AO intensity.
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216 | float cosAngle = .5f + dot(sampleNormal, -normal) * 0.5f;
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217 | // use binary decision to cull samples that are behind current shading point
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218 | cosAngle *= step(0.0f, dot(dirSample, normal));
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219 |
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220 | // the distance_scale offset is used to avoid singularity that occurs at global illumination when
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221 | // the distance to a sample approaches zero
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222 | //const float aoContrib = SAMPLE_INTENSITY / (DISTANCE_SCALE + lengthToSample * lengthToSample);
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223 | const float aoContrib = SAMPLE_INTENSITY / sqrLen;
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224 | //const float aoContrib = (1.0f > lengthToSample) ? occlusionPower(9e-2f, DISTANCE_SCALE + lengthToSample): .0f;
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225 |
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226 | #if 1
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227 | // if surface normal perpenticular to view dir, approx. half of the samples will not count
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228 | // => compensate for this (on the other hand, projected sampling area could be larger!)
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229 |
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230 | const float viewCorrection = 1.0f + VIEW_CORRECTION_SCALE * max(dot(viewDir, normal), 0.0f);
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231 | total_ao += cosAngle * aoContrib * viewCorrection;
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232 | #else
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233 | total_ao += cosAngle * aoContrib;
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234 | #endif
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235 | // check if the samples have been valid in the last frame
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236 | validSamples += (1.0f - step(1.0f, lengthToSample)) * sampleColor.x;
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237 |
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238 | ++ numSamples;
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239 | }
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240 |
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241 | total_ao /= numSamples;
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242 |
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243 | return float3(max(0.0f, 1.0f - total_ao), validSamples, numSamples);
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244 | }
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245 |
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246 |
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247 | /** The ssao shader returning the an intensity value between 0 and 1.
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248 | This version of the ssao shader uses the dotproduct between
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249 | pixel-to-sample direction and sample normal as weight.
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250 | */
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251 | float3 ssao(fragment IN,
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252 | sampler2D colors,
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253 | sampler2D noiseTex,
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254 | float2 samples[NUM_SAMPLES],
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255 | float3 normal,
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256 | float3 centerPosition,
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257 | float scaleFactor,
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258 | float3 bl,
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259 | float3 br,
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260 | float3 tl,
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261 | float3 tr,
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262 | float3 viewDir,
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263 | float newWeight
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264 | )
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265 | {
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266 | // Check in a circular area around the current position.
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267 | // Shoot vectors to the positions there, and check the angle to these positions.
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268 | // Summing up these angles gives an estimation of the occlusion at the current position.
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269 |
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270 | float total_ao = .0f;
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271 | float validSamples = .0f;
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272 | float numSamples = .0f;
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273 |
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274 | for (int i = 0; i < NUM_SAMPLES; ++ i)
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275 | {
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276 | const float2 offset = samples[i];
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277 |
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278 | #if 1
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279 | ////////////////////
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280 | //-- add random noise: reflect around random normal vector (rather slow!)
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281 |
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282 | float2 mynoise = tex2Dlod(noiseTex, float4(IN.texCoord * 4.0f, 0, 0)).xy;
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283 | const float2 offsetTransformed = myreflect(offset, mynoise);
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284 | #else
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285 | const float2 offsetTransformed = offset;
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286 | #endif
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287 | // weight with projected coordinate to reach similar kernel size for near and far
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288 | //const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor + jitter;
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289 | const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor;
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290 |
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291 | const float4 sampleColor = tex2Dlod(colors, float4(texcoord, .0f, .0f));
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292 | const float3 samplePos = ReconstructSamplePos(sampleColor.w, texcoord, bl, br, tl, tr);
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293 |
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294 |
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295 | ////////////////
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296 | //-- compute contribution of sample using the direction and angle
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297 |
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298 | float3 dirSample = samplePos - centerPosition;
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299 |
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300 | const float sqrLen = max(SqrLen(dirSample), 1e-2f);
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301 | const float lengthToSample = sqrt(sqrLen);
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302 |
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303 | dirSample /= lengthToSample; // normalize
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304 |
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305 | // angle between current normal and direction to sample controls AO intensity.
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306 | const float cosAngle = max(dot(dirSample, normal), .0f);
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307 | const float aoContrib = SAMPLE_INTENSITY / sqrLen;
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308 | //const float aoContrib = (1.0f > lengthToSample) ? occlusionPower(9e-2f, DISTANCE_SCALE + lengthToSample): .0f;
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309 |
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310 | #if 1
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311 | // if surface normal perpenticular to view dir, approx. half of the samples will not count
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312 | // => compensate for this (on the other hand, projected sampling area could be larger!)
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313 |
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314 | const float viewCorrection = 1.0f + VIEW_CORRECTION_SCALE * max(dot(viewDir, normal), 0.0f);
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315 | total_ao += cosAngle * aoContrib * viewCorrection;
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316 | #else
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317 | total_ao += cosAngle * aoContrib;
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318 | #endif
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319 |
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320 | // check if the samples have been valid in the last frame
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321 | // hack: the distance measure can fail in some cases => choose something different
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322 | const float tooFarAway = step(1.0f, lengthToSample);
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323 | validSamples += (1.0f - tooFarAway) * sampleColor.x;
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324 | //validSamples += sampleColor.x;
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325 |
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326 | ++ numSamples;
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327 |
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328 | //if ((validSamples < 1.0f) && (newWeight > 200) && (numSamples >= 8)) break;
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329 | if ((validSamples < 1.0f) && (numSamples >= 8)) break;
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330 | }
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331 |
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332 | total_ao /= numSamples;
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333 |
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334 | return float3(max(0.0f, 1.0f - total_ao), validSamples, numSamples);
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335 | }
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336 |
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337 |
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338 |
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339 | /** The mrt shader for screen space ambient occlusion
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340 | */
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341 | pixel main(fragment IN,
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342 | uniform sampler2D colors,
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343 | uniform sampler2D normals,
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344 | uniform sampler2D noiseTex,
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345 | uniform float2 samples[NUM_SAMPLES],
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346 | uniform sampler2D oldTex,
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347 | uniform float4x4 modelViewProj,
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348 | uniform float4x4 oldModelViewProj,
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349 | uniform float temporalCoherence,
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350 | uniform float3 bl,
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351 | uniform float3 br,
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352 | uniform float3 tl,
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353 | uniform float3 tr,
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354 | uniform float3 oldEyePos,
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355 | uniform float3 oldbl,
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356 | uniform float3 oldbr,
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357 | uniform float3 oldtl,
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358 | uniform float3 oldtr,
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359 | uniform sampler2D attribsTex
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360 | )
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361 | {
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362 | pixel OUT;
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363 |
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364 | //const float3 normal = normalize(tex2Dlod(normals, float4(IN.texCoord, 0 ,0)).xyz);
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365 | const float3 normal = tex2Dlod(normals, float4(IN.texCoord, 0 ,0)).xyz;
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366 |
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367 | // reconstruct position from the eye space depth
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368 | const float3 viewDir = IN.view;
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369 | const float eyeSpaceDepth = tex2Dlod(colors, float4(IN.texCoord, 0, 0)).w;
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370 | const float4 eyeSpacePos = float4(-viewDir * eyeSpaceDepth, 1.0f);
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371 |
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372 | float3 diffVec = tex2Dlod(attribsTex, float4(IN.texCoord, 0, 0)).xyz;
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373 |
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374 |
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375 | ////////////////
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376 | //-- calculcate the current projected posiion (also used for next frame)
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377 |
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378 | float4 projPos = mul(modelViewProj, eyeSpacePos);
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379 | const float invw = 1.0f / projPos.w;
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380 | projPos *= invw;
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381 | float scaleFactor = SAMPLE_RADIUS * invw;
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382 |
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383 |
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384 | /////////////////
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385 | //-- compute temporal reprojection
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386 |
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387 | float2 temporalVals = temporalSmoothing(eyeSpacePos, eyeSpaceDepth, IN.texCoord, oldEyePos,
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388 | oldTex, oldModelViewProj,
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389 | colors,
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390 | projPos.xyz,
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391 | invw,
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392 | oldbl, oldbr, oldtl, oldtr,
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393 | diffVec
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394 | );
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395 |
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396 | const float oldSsao = temporalVals.x;
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397 | float oldWeight = temporalVals.y;
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398 |
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399 | float3 ao;
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400 |
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401 | // cull background note: this should be done with the stencil buffer
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402 | //if (SqrLen(diffVec < 1e6f) && (eyeSpaceDepth < 1e10f))
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403 | if (eyeSpaceDepth < 1e10f)
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404 | {
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405 | ao = ssao(IN, colors, noiseTex, samples, normal, eyeSpacePos.xyz, scaleFactor, bl, br, tl, tr, normalize(viewDir), oldWeight);
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406 | //ao = ssao2(IN, colors, noiseTex, samples, normal, eyeSpacePos.xyz, scaleFactor, bl, br, tl, tr, normalize(viewDir), normals);
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407 | }
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408 | else
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409 | {
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410 | ao = float3(1.0f, 1.0f, 1.0f);
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411 | }
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412 |
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413 | const float squaredLen = SqrLen(diffVec);
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414 |
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415 | if ((ao.y > 1.0f) && (squaredLen < DYNAMIC_OBJECTS_THRESHOLD))
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416 | {
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417 | oldWeight = min(oldWeight, 4.0f * NUM_SAMPLES);
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418 | }
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419 |
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420 | const float newWeight = ao.z;
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421 |
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422 | // blend between old and new samples (and avoid division by zero)
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423 | OUT.illum_col.x = (ao.x * newWeight + oldSsao * oldWeight) / max(1e-6f, (newWeight + oldWeight));
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424 | OUT.illum_col.y = clamp(newWeight + oldWeight, .0f, temporalCoherence);
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425 | OUT.illum_col.z = SqrLen(diffVec);
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426 | OUT.illum_col.w = eyeSpaceDepth;
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427 |
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428 | return OUT;
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429 | }
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